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Browsing by Subject "change detection analysis"

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    Item type:Article, Access status: Open Access ,
    Unmanned Aerial Vehicles for three‑dimensional mapping and change detection analysis
    (Wydawnictwa AGH, 2021) Gbopa, Adetola Olufunmilayo; Ayodele, Emmanuel Gbenga; Okolie, Chukwuma John; Ajayi, Akinwumi Olaitan; Iheaturu, Chima Jude
    Unmanned Aerial Vehicles (UAVs), commonly known as drones are increasingly being used for three‑dimensional (3D) mapping of the environment. This study utilised UAV technology to produce a revised 3D map of the University of Lagos as well as land cover change detection analysis. A DJI Phantom 4 UAV was used to collect digital images at a flying height of 90 m, and 75% fore and 65% side overlaps. Ground control points (GCPs) for orthophoto rectification were coordinated with a Trimble R8 Global Navigation Satellite System. Pix4D Mapper was used to produce a digital terrain model and an orthophoto at a ground sampling distance of 4.36 cm. The change detection analysis, using the 2015 base map as reference, revealed a significant change in the land cover such as an increase of 16,306.7 m2 in buildings between 2015 and 2019. The root mean square error analysis performed using 7 GCPs showed a horizontal and vertical accuracy of 0.183 m and 0.157 m respectively. This suggests a high level of accuracy, which is adequate for 3D mapping and change detection analysis at a sustainable cost.